The present invention relates to a display apparatus.
Conventionally known types of display apparatus include those that use a photographic film such as slide projectors, those that display images on an image-receiving tube using image signals, and the like.
However, in these conventional display apparatus, it is not possible to display images that have a high resolution and so a display apparatus that enables high resolution image display is required.
In order to display high resolution images, one display apparatus has been developed which has a spatial light modulator of reflective type having a configuration that includes a photoconductive layer member between two electrodes, a photomodulation layer member having a photomodulating material that changes the optical nature such as the status of light scattering, birefringence and rotary polarization of light incident thereto in accordance with an electrical field applied thereto.
FIG. 1 is a view of one configuration of a conventional display apparatus using a spatial light modulator SLM of reflective type provided with a photomodulation layer member using a photomodulating material that performs birefringence operation.
The spatial light modulator SLM in FIG. 1 has a power source E connected to electrodes Et1 and Et2 and has an electrical field applied to a photomodulation layer member PCL, so that when a writing light WL is irradiated to the spatial light modulator SLM from the side of the electrode Et1 in the status where the optical intensity of the writing light WL is modulated by the information which is the object of display, that irradiated light WL passes through the electrode Et1 to reach the photoconductive layer member PCL.
The value of the electrical resistance of the photoconductive layer member PCL changes in accordance with the intensity distribution of the light WL that reaches it. This results in a charge image generated having an intensity distribution that corresponds to the intensity distribution of the light WL on the boundary surface between a dielectric mirror DML and the photoconductive layer member PCL.
When non-polarized light radiated from a light source LS via a lens L is incident to a polarization beam splitter PBS, only the S-polarized light is reflected by the beam splitter PBS.
The S-polarized light is irradiated to the spatial light modulator SLM on which the charge image is formed on the side of the electrode Et2 via beam splitter PBS as a reading light RL.
The S-polarized reading light RL passes through a photomodulation layer member PML of birefringence type and is then reflected by a dielectric mirror DML, again passes through the photomodulation layer member PML and is irradiated from the electrode Et2 in the status where the polarization plane of the reading light RL changes in accordance with the charge image described above.
The reading light RL irradiated from the electrode Et2 is irradiated to the polarization beam splitter PBS and only the P-polarized light RLr is applied to a projection lens Lp and is projected to a display screen S.
In the conventional display apparatus shown in FIG. 1, the reading light RL is irradiated parallel to the optical axis of the spatial light modulator SLM and the projection lens Lp is provided along the path of the light RLr irradiated from the polarization beam splitter PBS. So the back focal distance (the distance between the modulator SLM and the lens L.sub.p) becomes large and a wide angle lens cannot be used, accordingly there is the problem that the configuration of a display apparatus that displays large-screen images cannot be made compact.